In order to prevent the entrance of moisture along with oxygen, various contrivances have been made to many elements and devices utilizing oxygen in air, such as air cells and fuel cells. In the case of an air cell, for example, the entrance of water vapor in the atmosphere into the cell causes the concentration change or volume change of the electrolyte, thus degrading the discharge characteristics.
Therefore, it has been proposed to provide an oxygen-selective permeable film comprising a siloxane-based compound and an oxygen-permeable solution layer at the air intake opening of an air cell, thereby preventing the entrance of water vapor in the atmosphere into the cell (Patent Document 1).
Further, an air cell has also been proposed in which a uniform film or the like is provided with plural permeable pores of not more than 300 μm for passing air and that uses this as a selective permeable film for inhibiting the permeation of water vapor (Patent Document 2).
Further, although not in the field of batteries, in the case of a radio antenna used in a heavy snowfall area, snow or ice attached to the surface of the antenna may reduce the electric field strength, thus causing deterioration in the quality of telecommunication. In order to prevent this, a technique is available in which PTFE (polytetrafluoroethylene) particles are applied as the snow resistant material to the surface of the antenna, using a binder (Non-Patent Document 1).
Patent Document 1: Japanese Laid-Open Patent Publication No. Sho 59-75582
Patent Document 2: Japanese Laid-Open Patent Publication No. Hei 6-44954
Non-Patent Document 1: Super water-repellency and super water-repellent technology, published by Technical Information Institute Co. Ltd., p. 155-163